Sheet-steel crank case



Nov. 3 '1925 W. J. FOSTER SHEET STEEL LCRNK .CASE

F'iled Jan. 1120. 1922 Nov. 3, 1925.

- W. J. FOSTER SHEET STEEL GRANK cJAsE- 4 Sheets-Sheet 2 Filed Jan. 20. 1922 fuma/13 Nov.

W. J. FOSTER SHEET STEEL GRANK CASE Filed Jan. 20, 1922 4 Sheets-Sheet 5 www Nov. 3,1925. 1,560,342

W. J. FOSTER SHEET STEEL CRANK CASE A Filed Jan. 20. 1922 4 Sheets-Sheet 4 specification.

Patented Nev.. 3, 1925,

WILLIAM J'. FOSTER, OF DAYTON, OHIO.

SHEET-STEEL CRANK CASE.

Application med January 2o, 1922. serial No. ssoso.

To all 'wlw/m, t may concern.:

Be it known that I, VViLLiAM J. Fos'riiu, a citizen 0f the United States, residing at Dayton, in the county of Montgomery and State of4 Ohio, have invented certainnew and useful Improvements in Sheet-Steel Crank Cases, of which the following is a This invention relates to an improved crank case construction for internal combustion engines and is particularly applicable to the engines of aircraft by reason of the strength, lightness, rigidity and durability of the resulting structure. Y

Thel primary objeet'of the invention is to provide a crank case having the main struc` tural members and outer casing of steel plate and sheet steel formed into the required shape and joined together preferably by welding.

The invention' is described in the following specification in connection with the accompanying drawings, in which:

Figzl is a side elevation of the upper section of the crank case;

Fig. 2 is a cross-section on the line 2-2 of Fig. 1, said line being the center line of the cylinders; A

Fior. 3 is a plan view at the top, and a partial horizontal sectional view, at the bottom, of theupper section of the crank case;

Fig. 4 is a sectional view on the line 4-4 of Fig. 25 Fig. 5 1s -a plan View of the lower section of the crank case;

Fig. 6 is a sectional view on the line 6-6 of Fig. 5; and l.

Fig. 7 is a side elevation of the assembled crank case.

The invention is illustrated as applied to a V-type engine. A top master plate 10, hav- Aing openings 11 formed therein corresponding to bore of the cylinders, and of suitable shape to conform to the outline of the cylin der flanges is bent to the angle of the top of the crank case. Immediately beneath the master plate 10 is located the outer casing 12 which is provided with circular openings 13 corresponding to openings 11 of the master plate. This outer casing is preferably composed fof sheet steel formed to the desired shape of the crank case. A bottom master plate 14 is of substantially rectangular shape and 'is provided with spaced cross pieces and ends which are bent upwardly at an intermediate portion tov form arcuate depressions 15 for receiving the bearings for the main journals` of a crankshaft. The

outer casing 12 extends down the sides of the crank case and is bent over at 16 to joint the bottom master plate 14.@

Spaced transverse Webs are placed between the up er and lower master plates and each consists mainly of a quadrilateral frame 17 having a T-shaped section, as shown in Fig. 4, and composed of angles 18 or angularly ybent plates placed back to back.

The angles 18 are joined to the outer casing 12, the lower master plate, and to U-shaped pieces 19. A plate which may be composed of a single sheet or a plurality of metallic sheets 20 extends longitudinally through the central part of the upper half of the crank case. The angles 18 are joined to the loop of the U-shaped pieces 19, and the outer ends of the armsof the latter are bent outwardly,at 21 and joined preferably by Welding to opposite sides of the central sheet 20. Sheet 20 may be arched or cutaway between bearings when necessary in order to provide clearance for the crank pins of the crankshaft. The central sheets I20 are bent over at the topto form flanges 22 which are joined to the outer casing 12 at the ridge of the crank case. shaped pieces 19 are provided with bottom ianges 23 and 24. The lianges 23 are arcshaped to provide a support for the main bearings of the crankshaft and these anges are secured to the -arcuate portions 15 of the bottoni master plate 14. The flanges 24 of the end webs are also secured to the bottom master plate 14 which is provided with a ertures 25 adapted to receive the main holddown studs 26. These studs ass upward through Ithe space Aprovided tween the The sides of the U- sides of "the U-shaped pieces 19, as shown in 'receive the bolts (not shown) which fasten 'the crank case to the support of the engine. The outer casing at the top thereof is provided with a series of spaced depressions ing thus reinforced by plates forms seats for the nuts (not shown) which engage the main hold-down studs 26. Studs 36 pass through threaded apertures 37 in the top master plate 10 Vfor the purpose of fastening the engine cylinders to the crank case. The

bottom master plate 14 is formed with spaced apertures 38 for receiving the bo-lts which fasten the upper and lower sections of the crank case together.

The lower section of the crank case, illustrated in Figs. 5 and 6, has a top master plate 40 which is provided with spaced apertures 41 adapted to register with the apertures 38 of the bottom masterplate of its upper section for receiving the fastening bolts. The master plate is of substantially rectangular shape and is provided with spaced cross pieces and ends whichiare formed with intermediate arc-shaped depressions 42 adapted to receive the bearings `for the main journals of the crankshaft. The lower half of the crank case is braced by a skeleton frame having spaced transverse webs built up of a central unit and duplicate outer units. The central unit is somewhat triangular in shape and is oo mposed of angle pieces 43 placed back to back so as to form -a T-section. The duplicate outer units are also of triangular shape inverted in regard to the central section and formed by angle pieces 44 placed back to back. An upper outside casing 45 composed of sheet steel is bent around the lower apex of the end units as at 46 and thence extends upward between the flanges of angles 43,44 to the plate 40, as designated by the numeral 47. The angle pieces 43, 44 and extensions 47 of the outer casing are welded together. The angles 44 are also secured to the outer casing 45 and to the master plate 40. The triangular shapes of the central and outer du licate units are slightly distorted by provi `ing circular portion-s 48, 49 which are secured to the arcshaped portions 42 vof the master plate for the purpose of reinforcing the same.

A sheet 50 having rectangular openings 51 therein is attached to the lower side of the base of the central units and the op site ends of this sheet are bent downwardly so as to form the angularly disposed longitudinally, extending flanges 52. A lower outsidecasing 53 overlaps the upper outside casing 45 and is secured thereto and to the flanges 52. The angles 44 are formed with recesses 54 having located therein they nuts 554 which are fixed to the underside of the top master plate 40. The main holddown studs 26 pass through appropriate apertures in the master plate and are screwed into the nuts 55.

It will be noted that theframe of the crank case is braced laterally and longitudinally, laterally by the pieces 17, 19, 43 and 44, and longitudinall by the pieces 2O and 50. This skeleton ramework is also stiffened and braced around its exterior by the' sheet steel casings 12l and 45, and rendered extremely rigid and resistant to distortions in a diagonal direction by the adjacent master plates 14 and 40 and the top master plate 10. The master plates 14 and 40 are preferably provided with cross pieces at each web, arched as at 15 and 42 and welded to the lateral bracing so that each main bearing is rigidly mounted. The two halves of each bearing are held together with the proper pressure by means of suitable nuts which engage the threaded ends of studs 26 projecting above plates 35. If desired the whole assembly may be brazed as a unit by dipping in molten spelter which will insure a unitary structure. The element of lightness so important in engines of aircraft is secured my making the lateral and longitudinal bracing, in fact the whole framework or skeleton, of steel stampings, whereby lightness and sturdiness is obtained.

This type of construction while extremely light and rigid is not subject to crackingas in the case of castings, which frequently have hidden defects. The fabricated type of construction above described is also particularly adapted to quantity production since the various parts may be stamped or drawn to desired form very rapidly by well known means and then assembled even by unskilled labor.

Whereas the invention hasbeen described as applicable to V-type internal combustion engines for aeronautical uses, it is also applicable to vertical, horizontal, radial, or other cylinder arrangements, and lends itself` readily to automobile work or to high speed steam engines and the like, where durability, strength, lightness and rigidity are the determining factors.

1.l Acrank case comprising an upper and a`- lower section, each section including a skeleton framework having longitudinal and lateral bracing members formed of sheet metal stampings.

2. A crank case having an upper and a lower section, each section consisting of a skeleton framework having lon itudinal and lateral bracing members, an master plates having cross pieces provided -with arcuate portions for receivlng the .main bearings of the crankshaft.\

8. A crank c as'e comprising'an upper and a lower section, each section consisting of a skeleton framework having longitudinal and lateral bracing members and master plates bracing the framework' against distortion.

4. A crank case comprising an upper and `a lower section, each section consisting of a skeleton framework having longitudinal and lateral bracing members, and a sheet metal casing, the framework and casing being homogeneously secured together to form a unitary structure.

5. A crank case for engines having an upper and a lower section, said upper section comprising, a skeleton framework formed of metal stampings, a sheet metal outer casing rigidly secured to said framework, a

bottom master plate secured to -said frame-l work and casing and adapted to be detachably connected to the lower section, and a top master plate secured tn said framework ,and casing and adapted to be detachably tural units of angle pieces placed back to back, U-shaped structural pieces secured to said end units, and a'central longitudinally extending sheet joined to said U-shaped structural pieces.

8. A crank case for engines having an upper and a lower section, said upper section consisting of transverse webs having end structural units of angle pieces, U-shaped structural pieces secured to said end units, an outer sheet metal casing secured to said webs, and studs attached to the lower section passing upward between the sides of said U-shaped structural pieces and through the casing for firmly holding said sections together.

9. A crank case for engines having an upper and a lower section, transverse webs in said upper and lower sections arranged in vertical alignment, said Webs being adapted to support the main bearings for the crankshaft of the engine, a sheet metal outer casing secured to the transverse webs of said upper section and studs secured to the lower section and passing through said outer casing for holding said main bearings in proper adjustment.

10. In a crank case, an upper section having a skeleton framework, an outer sheet metal casing secured to said framework, and corrugated sheet metal bracing members secured to the sides of Said casing.

11. In a crank case for engines, a lower section comprising a master plate having cross pieces bent intermediately to arcuate form for receiving the lower half of the main bearings for a crankshaft, and transverse webs composed-of structural members having portions thereof conforming to said arcuate form and secured to said cross pieces in order to reinforce the latter at the main bearings.

12. In a crank case, a lower section comprising transverse webs composed of a central and end units, andan outer casing of'sheet metal bent so as to have a portion thereof interposed between and secured to said central and end units.

131 In a crank case, a lower section coniprisng transverse webs,an apertured sheet extending longitudinally and secured to said webs, an upper casing fastened to said webs, and a lower casing attached to said 'upper casing and sheet. u

14. A crank case comprising upper and lower sections provided with master plates adapted to be detachably connected together, cross webs in said upper and lower sections providing a support for the main bearings'of the crankshaft of the engine, metal casings secured to the webs of the upper and lower sections respectively,l and means passing through the said casing of the upper section for maintaining the main bearings in proper adjustment. e

In testimony whereof IV affix my signature.

WILLIAM J. FOSTER. 

